Unless you have a very large amount of data I find it unlikely that you would many if any entries which happened on midnight when rounded to the nearest second. If you do though surely just showing the date does not tell the user enough information to let them know it happened at midnight especially if viewed without context e.g. on it's own
–
CodeBlendAug 3 '11 at 14:38

It was graphing a very large amount of data. Hundreds of thousands of points. What I want to format is the X axis labels, most of the times they're rounded its from midnight to midnight, but when you zoom in, you need the H:M:S. The microsoft charts package im using allows for a single format string to be entered. Unfortunely, I don't think I can get the format I want that way, and will have to add some custom code.
–
greggorob64Aug 3 '11 at 15:45

I will prolly end up using this. Its not a perfect solution (the microsoft charts package doesn't allow selective formatting without adding extra code), but I think its the best solution. Thanks!
–
greggorob64Aug 3 '11 at 15:46